Thermostat.



PATBNTED OCT. 24, 1905.

F. W. ROBERTSHAW.

THERMOSTAT.

APPLICATION FILED 11213.10, 1904.

TIIE

STATES FREDERICK W. ROBERTSHAVV, OF PITTSBURG, PENNSYLVANIA.

T l-l E R NI O S TAT Speecation of Letters Patent.

Patented. Get. 24, 1905.

Application lefl February 10, 1904:. Serial No. 192,955.

` .To fir/N whom, t may cow/cern:

Be it known that I, FREDERICK W. ROBERT- sHAw, a resident of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Thermostats; and I do hereby declare the following to be a full, clear, and exact description thereof.

My invention relates to thermostats and gasvalves for controlling the iow of gas to the burners of water-heaters and the like, according to the temperature of the water in the system.

One of the objects of my invention is to provide a thermostat of this character which is very sensitive and reliable and which will increase the iiow of gas as soon as even a small quantity of hotwater is drawn from the system.

A further object of my invention is to provide a device of this kind which can be readily adjusted and without the necessity of stopping the flow of gas or interfering with the inclosed and concealed portions of the device.

In the accompanying drawings, Figure 1 is a vertical section through my thermostat and gas-valve. Fig. 2 is asimilar view, on an enlarged scale, of the lower portion of Fig. 1; and Fig. 3 is an inverted plan view of the gas-valve.

My invention may be employed with waterheating systems of any kind, such as ordinary domestic systems found in dwelling-houses, or may be employed for hot-water-heating systems. It depends for its operation upon the different coefcients of expansion of two bodies, one of which is connected to the casing of the gas-valve and the other of which is connected to the valve and one of which is a portion or section of a circulation-pipe of the system.

In the drawings, 1 represents a pipe-section which will be a portion of the circulation-pipes of the system. This pipe-section is provided at one end with a port 2, communicating with i-the boiler or reservoir of the system, and at its opposite end with a port 3, which will be connected to the coil or other water-heater. This pipe-section is composed of a material, such as brass, having a comparatively high coefficient of expansion.

5 represents the casing of the gas or other fuel valve, this casing being suitably connected to the pipe-section 1, as by providing the same with a yoke 6, having a threaded or other connection with the lower end of the pipesection 1. The valve-casing' is provided with an inlet 9, which will be connected by a suitable pipe to a source of fuel-supply, and with an outlet 10, which will be suitably connected to the burners of the water-heater. It is provided with a valve-seat 11, with which coperates a disk-valve 12. This valve is connected to a stem or rod 18 in any suitable manner, such as being screwed thereon, as shown. The disk is provided with a pair of wings 14, whereby it can be turned onto and olf said rod. In order to increase the sensitiveness of the valve and to overcome or reduce the friction of the gas flowing through the same and also to overcome the possibility of dirt or dust lodging between the disk and val veseat, said disk is so constructed that it will have only a narrow bearing on the valve-se it. To this end the seating portion of the disk is formed as an annular rib or bead 15, which may be formed in any suitable way-21s, for instance, providing the upper face of the disk with a groove 16, leaving outside of the same the rib 15. Hence as soon as the valve is separated slightly from its seat the gas will pass readily through the saine, the narrow rib l5 greatly reducing the friction of the gas in passing through. Furthermore, dust and the like cannot lind lodgment on this narrow rib, thus insuring a clean face for seating on the valve-seat. The disk is thin and flexible at its central portion, preferably by haring annular grooves or corrugations 17 formed therein, so that it will yield. and relieve the threaded connections of the rod 13 of excessive strain, as might otherwise occur if the litting overheated or if there is any obstruction to the closing of the valve. The disk is also provided with a leak-opening' 18 to relieve eX- cessive gas-pressure on either side thereof.

The lower end of the valve-casing is closed by a screw-cap 19, which will permit access to the interior of the valve-casing for cleaning and the like. The rod 13 passes through the upper wall of the valve-casing, and leakage is prevented at this point by a stulliugbox 20. This rod extends up through the pipe-section l and is secured tothe upperend of the latter and is constructed of steel or other material having a materially smaller coeiiicient of expansion than the tube 1. Steel is preferred, as its coeiiicient of expansion rcmains practically constant for all temperatures. Preferably the rod 13 will be so located with reference to the tube 1 as to be air-cooled, so that it will not be materially TOO aected by the heat in the tube 1. This ma f be accomplished in various ways, such as by. locating the rod 13 outside of the pipe-section 1; but preferably the tube 1 will be formed double-that is, provided with an inner tube '21, secured tight at the upper and lower ends of the pipe-section 1 and open both at its upper and lower ends to the atmosphere and of considerably larger size than the rod 13. As a consequence air can circulate up through the inner pipe 21, thus always keeping the rod 13 air-cooled and preventing the same from being materially affected by the heat of thewater in the pipe-section 1. As a consequence even a slight increase or decrease of temperature in the pipe-section 1 will expand or contract the latter, but without materially affecting the rod 13, thus moving the valveseat relatively to the valve and varying the flow of gas to the burners. Then the rod 13 is air-cooled, as shown, it may even be of the same material as the pipe-section l, the relative movements of these parts depending in that case not upon the dierent coefficients of expansion thereof, but entirely upon the fact that one of said members is subjected to the varying temperatures of the water, whereas the other remains at practically a constant temperature; but as the rod 13 may to some extent be affected by the heat in the pipe-section 1 it is preferable to make it of material having a lesser coefhcient of expansion than said pipe-section.

The threaded connection between the diskvalve 12 and the rod 13 will serve to adjust the apparatus in assembling the same; but as adjustments maybe necessary after the apparatus is installed I provide other adjusting means which will be accessible without opening the gas-valve or otherwise interfering with the internal mechanism of the apparatus. To this end the upper end of the rod 13 is secured to a yoke' 22, this union being affected in any suitable way, such as having the rod passing through an opening in said yoke and secured therein by means of a set-screw 23. This yoke has a threaded connection with the upper end of the pipe-section 1, so that by merely turning the yoke on said pipe-section relative movement between the rod 13 and pipe-section is effected and the adjustment thus obtained. A set-screw 25 is provided for locking the yoke in its adjusted position.

Both the yoke 6 for the gas-valve and the yoke 22 at the upper end of the device are open, thus permitting the free circulation of air up through the inner pipe 21. This construction not only keeps the rod 13 cool, but the air circulation also carries off any condensation, and the fouling of the rod is thereby avoided. Any condensation or leakage that occurs will escape through the open yoke 6 and cannot get into the gas-valve and mix with the gas. This inner pipe may be secured to the pipe-section l in any suitable temperature of the water in the system.

way and may be even integral therewith. As, however, there is liable to be some slight difference in the extent of expansion of the inner and outer tubes, I provide a stufiing-box 26 at either one or both ends of said tubes, the drawings showing such stufng-box at the upper end of the tube.V

In use the pipe-section 1 will be placed in the circulation-pipes of the system, preferably between the ordinary boiler or reservoir and the heating-coil. The water of the system will circulate through the same, preferably downwardly, and consequently the device will be affected by the heat of the water in the system. As long as the water liowing through the system is cold the pipe-section 1 will remain contracted, thus holding the disk 12 away from the valve-seat and permitting' the g'as or other fuel to iiow to the burners of the heater. As soon, however, vas the water flowing through the system becomes hot its circulation through the pipe-section 1 will expand the latter, and as the rod 13 remains substantially cold it will cause a closing of the fuel-valve, thus decreasing the heat at the burners, and as soon as the water has reached the temperature for which the thermostat has been set the fuel-valve will be entirely closed, thus shutting olf the flow of all fuel to the burners. cools again the pipe-section 1 will contract, thus again opening' the fuel-valve and increasing the heat at the burners. In this manner the temperature in the system will be automatically maintained. The construction of the gas-valve is such that friction of the gas in passing between the disk and valve-seat is largely overcome, and dust and the like cannot lodge between the valve and its seat so as to cause leakage of gas. The leak-opening through the disk-valve permits a slight leakage of gas and relieves any tension or pressure that may occur in the gas-pipes.

Inasmuch las the rod 13 is .air-cooled, and thus not affected by the heat in the pipe-sec* tion 1, the device is rendered very sensitive, moving the valve at only slight changes in The adjustment of the device can be secured without opening the gas-valve by merely turning the yoke 22. The device as a whole is very simple and is not liable to disarrangement.

lVhat I claim as my invention, and desire to secure by Letters Patent, is-

1. A thermostatic device .for water-heaters comprising a section of circulation-pipe, a valve-casing' attached thereto and provided with a valve-seat and inlet and outlet ports, a valve cooperating with said seat, a rod secured to said valve and extending through said pipe-section and through an opening in the end thereof, and a yoke on the upper end of said rod, said yoke having internal threads engaging external threads on the pipe-section whereby to adjust the valve with relation to As soon as the water in the systemr its seat, said rod and pipe-section being cornposed of metals having diierent coefficients of expansion.

Q. A thermostatic device Vfor water-heaters comprising1 a section or' circulation-pipe, a valve-casing attached thereto and provided with a valve-seat and inlet and outlet ports, a valve cooperating with said Seat, said pipesection comprising outer and inner tubes, the latterbeing open to the air at bothends, and a rod connected to the valve and extending through the inner tube and secured to the opposite end ot' the pipe-section in a manner to leave a tree opening' to the inner tube.

3. A thermostatic device t'or water-heaters, comprising a Section of circulating-pipe cornprising an outer tube and an inner tube extending therethrough and open at both ends to the air, a valve-casing attached to said pipe-section and provided with a valve-seat and inlet and outlet ports, a valve cooperating with said seat, a rod connected to said valve and extending' through the inner tube, and adjustable means for connecting said rod to the opposite end of said pipe-section, said means being so arranged as to leave a free opening to the inner tube.

t. A thermostatic device for Water-heaters comprising' a section of circulating-pipe cornposed of an outer tube and an inner tube extending therethrough and open at both ends to the air, a valve-casing provided with a valve-seat and inlet and outlet ports, an open yoke for securing` said valve-casing to said pipe-section, a valve cooperating with said seat, a rod connected to said valve and extending through said inner tube, and an open ,voke connected to said rod and having an adjustable connection with the pipe-section.

5. A gas-valve for water-heaters comprising a casing provided with inlet and outlet ports, a valve-seat in said casing, a valve-operating rod extending into said casing, a diskvalve having a thin or weakened central portion attached to said rod and cooperating with the valve-seat, and a tlierinostatic device for operating said rod.

6. A therinostatic device for water-heaters comprising a section of circulation-pipe, a valve-casing attached thereto and provided with a valve-Seat and inlet and outlet ports, a rod secured to the pipe-section on the end opposite the valve-casing and projecting into said casing, said rod and pipe-section being composed of metals having different eoeilicients of expansion, and a disk valve having a thin or weakened central portion attached to said rod and cooperating with said valveseat.

In testimony whereof I, the said FREDER- ICK W. RoBnnTsi-mw, have hereunto set my hand.

FREDERICK W. ROBERTSHAW.

Witnesses:

ROBERT (l. To'r'rnN, F. W. WINTER 

